Petroelastic model of oolitic limestone at the core scale

The paper presents a technique for constructing a parametric petroelastic model of oolitic limestone on the core scale using the approaches of the Effective Medium Theory (Rock Physics), data on the microstructure of the rock, and the velocities of elastic waves in the rock. Parameters of the petroelastic model characterize the structure of the void space of the rock and include the shape of intergranular and oolitic pores, as well as the degree of connectivity of pores in the matrix and oolites. The results of petroelastic modeling justify the importance of taking into account the specific microstructure parameters of each particular rock for which this simulation is carried out.
Materials and methods
Approaches of the Eff e Medium Theory (Rock Physics), the method of generalized singular approximation, data on elastic wave velocities, images of thin sections, polished sections, and scanning electron microscopy (SEM).
Results
A petroelastic model of oolitic limestone is constructed on core scale. The degree of influence of the model parameters on the elastic wave velocities is investigated. It is shown that the constructed model is quite sensitive to these parameters. The same parameters of oolites and intergranular pores have a different effect on the speed of elastic waves. Redistribution of porosity between oolites and intergranular space leads to a significant change in the elastic characteristics of the rock.
Conclusions
The Rock Physics approaches are used to construct a petroelastic model of oolith limestone on a core scale from the rock microstructure and elastic wave velocities measured on samples. The method of velocity measurements allowed one to estimate the degree of rock heterogeneity on the sample scale and classify the rock as an isotropic one with embedding various inhomogeneities. Statistical characteristics of the parameters describing the void space structure are obtained: aspect ratio of oolitic and intergranular pores and coeffi ients of their connectivity. It is shown that for a fi ed total porosity a redistribution of the porosity between the mineral matrix and oolites can lead to a signifi ant change in the elastic wave velocities.